lost in texas

Hey guys,

I'm trying to plan the Italy portion of my trip, and could use some help from those of you who have spent some time there! I'm planning to use the rails for most of this trip, but I may need to rent a car/bike at some point too. Here are the areas I'd like to visit:

-- Venice
-- Bologna
-- Florence
-- Pisa (day trip)
-- Rome
-- Cirque Terre
-- Naples (or Sorrento)
-- Pompeii (day trip)

-- Offida: this is a small town where my family's ancestry can be traced to. Located in the Marche region, near the east coast, I'm thinking I may need to rent transportation to get around in this province.

Are all these places worth seeing in one trip (within 3 weeks or so), or should I narrow it down a bit? What order would be most efficient based on the rail system? Any thoughts you could share would be really helpful...

Thanks!

__________________
"Men are not prisoners of fate, but only prisoners of their own minds."
-- FDR